Proton conducting membranes based on electrolyte filled microporous matrices

Polysulfone and microglass fiber fleeces were used as microporous supports for electrolyte based composites. The membranes were prepared by impregnati ng the matrix with various inorganic acids as well as with a 5 wt.% Nafion( R) solution. Among the various combinations of microporous supports and ele ctrolytes both types of fleece filled with 5 mol/dm(3) H2SO4 and the microg lass fiber fleece impregnated with Nafion(R) (similar to 26 wt.% uptake) ex hibit a resistance similar to that of Nafion(R)-117 (0.530 Omega cm(2)), wh ereas the polysulfone fleece soaked in Nafion(R) shows a distinctively high er ohmic resistance. With regard to the material properties, the polysulfon e/H2SO4 composite exhibits a specific conductivity higher than Nafion(R) -1 17 but still more than an order of magnitude lower than expected on the bas is of the porosity of the support (83%) and the specific conductivity of th e acid. Therefore, the uptake of electrolyte seems to depend strongly on th e surface characteristics of the microporous support. H-2/O-2 fuel cell measurements with MEAs obtained by using a cold press tec hnique reveal performances comparable to MEAs with Nafion(R) 117 electrolyt e for both the polysulfone/H2SO4 composite and the microglass fiber/Nafion( R) composite. (C) 2001 Elsevier Science B.V. All rights reserved.